The present invention relates to a row crop attachment for a mobile harvesting unit, and more particularly, an improved drive arrangement for the feeder assembly adapted to feed crop material rearwardly along a passageway defined by side-by-side dividers.
A conventional row crop head for a forage harvester has two or more dividers defining passageways between adjacent fore-and-aft sides. During operation adjacent sides of paired dividers pass on opposite sides of standing stalk type crop material such as corn, maize, sorghum, etc. As the harvester unit travels across the field, gathering means mounted on the dividers engage the crop stalks as they are being guided rearwardly along the passageway. A severing mechanism is provided to sever the stalks a short distance above the ground. After the stalks are severed, the butt ends are gripped for appropriate delivery of the crop material to rearwardly disposed crop handling elements such as a consolidating auger, or infeed rolls at the inlet of a forage harvester base unit.
Various types of gathering means have been employed in the past in row crop heads for guiding and engaging standing crop material, as well as guiding, gripping and feeding severed row crops. For example, it is common to use endless chains trained about paired sprockets. Crop engaging elements such as fingers, lugs, rods, etc., are attached to or are integral with the chains and extend into a passageway defined by dividers. The chain and lug arrangement shown in U.S. Pat. No. 4,072,002 Feb. 7, 1978, to Larry E. Heller et al. is exemplary of this type of prior art gathering means.
Another common type of gathering means used for conveying stalks in row crop heads utilizes a serpentine array of belts mounted on chains and guided along a path adjacent to the crop passageway. In this arrangement, stalks are urged rearwardly by means of paired belts extending from adjacent dividers. An arrangement of this nature is shown in U.S. Pat. No. 3,961,466 issued June 8, 1976, to Virgil B. Martin et al. Numerous other types of row crop head gathering arrangements are used but in typical present day commercial harvesting machines they generally employ an endless flexible element such as a belt, chain or the like. To this end, there is still another known type flexible element similar to a snowmobile belt with integral lugs for performing the stalk engaging and conveying function. In all known arrangements the flexible element causes a relatively high frequency of failures regardless of durability due to the unavoidable wear characteristics in this area of the header caused by continuous crop contact, as well as dust, mud, abrasiveness of crop material, etc. Thus, due to normal wear, it is not uncommon to replace a gathering belt or chain several times during the lifetime of a row crop attachment.
Further, and of even more concern, when chain breakage occurs there is a likelihood of damage to the cutting mechanism of the forage harvester unit. Hardened steel, lugs, gathering fingers, elements of the broken chain, etc., can easily become intermixed with the crop material when a failure occurs and it is difficult to stop the conveyor before damage occurs to the cutterhead and shear bar. Many times an entire broken gathering chain assembly passes through the cutter mechanism before the chain failure is detected. In all instances, the cost of repair, as well as the amount of downtime to the basic unit is to the detriment of the operator.
In the copending application (noted above) filed in the name of Robert M. VanGinhoven and assigned to a common assignee, the above problems are overcome by providing a row crop head having unique gathering means comprising a feeder assembly having rigid members aligned with a passageway. A plurality of crop engaging elements are affixed to each rigid member and appropriate drive of the feeder assembly permits intermittent motion of the elements to urge crop material rearwardly. Although any convenient number of bars is encompassed by the feeder assembly in question, as a practical matter a low number, such as two, three or four has been the most effective due to cost considerations, weight factors, etc. The drive arrangement shown in the preferred embodiment of the copending application mentioned above comprise the subject matter of this invention. Although other drive arrangements have been contemplated and could be employed they necessitate positive drive coupling to both shafts to assure proper rotational characteristics. For example, if two bars or one bar are used, to avoid counter forces, the opposite ends must be initially and continually rotated in the same direction when the feeder assembly is coupled to the drive means. Thus, to assure proper bar rotation the rotatable members on which the bars are mounted must both be positively coupled to the drive shaft which adds to the cost and weight of the overall assembly. In this arrangement, there are more moving parts such as chains and sprockets, gears and shafts, etc., on the drive assembly which increases the chance of failure and downtime by virtue of the mere increase in the number of elements requiring service due to normal wear of drive mechanisms of this nature.